1. Field of the Invention
The present invention relates to an apparatus for phase-calibrating so as to eliminate phase shifts developed between two repeated square wave signals having equal frequency and duty cycles by automatically overlapping a phase of one signal on a phase of another signal.
2. Description of the Prior Art
A circuit using two repeated signals having equal frequency and duty cycles includes for example a synchronous detector circuit. Phase shifts are developed between a signal to be detected, which is one signal, and a synchronized clock, which is another signal, in said synchronous detector circuit. There has been no such technique of overlapping phases of two signals in the field of synchronous detecting of low frequencies (1 to 10 Hz), and there have therefore been disadvantages such as a small absolute value of the output signal, an inferior S/N ratio and the like.